What’s the best way to reduce the roughly half a million annual deaths from smoking in the US alone? Nearly half a million lives cut short, often with untold suffering, by a commercial product that has been known to kill its consumers for more than half a century.

We can raise the price of cigarettes through taxes, which is known to reduce demand, especially among young people who are the industry’s reservoir of future addicts to their legal product.

We can introduce plain packaging, which replaces the glamourous, glittery gold of Benson & Hedges with the graphic image of a lung destroyed by cancer. Or we can put warning labels on packs, in bus shelters, on TV. The possibilities are almost endless.

Many policy options exist, and research has shown that they work. Tobacco control policies save lives. They also save addicts the money they no longer pour into tobacco industry coffers.

No wonder, then, that the tobacco industry spent decades undermining the pervasive scientific consensus on the adverse health effects of tobacco.

So why are tobacco control measures now in place in many countries around the world? Why has the rate of smoking in California declined from 44% to less than 10% over the last few decades? Why can we now debate the policy options for a further reduction in public harm, such as plain packaging or tax increases?

It is because the public demanded action. This happened once the public realised that there was a scientific consensus that tobacco was harmful to health. The public wants action when they perceive that there is a widespread scientific agreement.

Those who wish to maintain a status quo, whether it involves tobacco or fossil fuels, have long understood this principle. In 2002, Republican strategist Frank Luntz advised politicians to undermine the scientific consensus on global warming, in order to influence their views on climate change. And the tobacco industry infamously stated that “doubt is our product since it is the best means of competing with the ‘body of fact’ that exists in the minds of the general public.”

A scientific consensus is necessary to understand and address problems that have a scientific origin and require a scientific solution. The public’s perception of that scientific consensus is necessary to stimulate political debate about solutions. When the public comes to understand the overwhelming agreement among climate scientists on human-caused global warming, acceptance of the science and support for climate action increase.

Consequently, one of the principal strategies of people who reject the scientific evidence on climate has been to try to maintain the consensus gap by creating the appearance of a scientific debate where there is none.

We should be talking about policy

There is clear evidence that closing the gap between the scientific consensus and the perception of it by the public is key to stimulating the constructive policy debate we should be having.

In a recent article, Mike Hulme argued that the debate “needs to become more political, and less scientific”. We agree, because the scientific debate has moved on from the fundamentals – there is no scientific debate about the fact that the globe is warming from human greenhouse gas emissions. So we need to hammer out political solutions rather than “debating” well-established scientific facts.

Hulme also suggested that, in reference to a paper by John Cook, “merely enumerating the strength of consensus around the fact that humans cause climate change is largely irrelevant to the more important business of deciding what to do about it.”

The data we have just reviewed show otherwise: there is strong evidence that the public’s perception of an overwhelming scientific consensus is key to stimulating the constructive policy debate we should be having.

Underscoring the consensus is therefore essential to counter the pseudo-scientific myths that are injected into the public debate by what scholarly evidence has recently revealed to be a nearly US$1 billion-a-year effort of political and vested interests in the US alone.

The infamy of those lobbying efforts is evident to anyone who understands the extent of the scientific consensus.

When Hulme queries the value of consensus on human-caused global warming in the peer-reviewed literature, he has it backwards in two important ways.

Closing the consensus gap is an important step towards the public debate about climate policy which he rightly calls for. The problem is the attack on climate science and the overwhelming consensus, not the research supporting it.